1. Field
One embodiment of the present invention relates to a server apparatus for use in, for example, a visual communication system (VCS), etc.
2. Description of the Related Art
A local area network (LAN) system has been used in an office and a business establishment. This LAN system accommodates, for instance, telephone sets, as extension terminals, in a telephone exchange, such as a private branch exchange (PBX) and a key telephone apparatus, and enables speeches among the extension terminals and an outside line communication network, such as a public network, and among mutual extension terminals by switch-connecting through the telephone exchange.
Recently, a system has been proposed, wherein a server, with data terminals (hereinafter referred to as client terminal(s)), such as video phone terminals and personal computers connected thereto, is connected to the telephone exchange via a transmission line then a voice communication system using the telephone exchange and a data communication system using the server work together.
By the way, in the foregoing system in which the telephone exchange and the server are arranged in parallel with each other, a VCS also has been strongly desired, in which the VCS configures a video conference, etc., by making data communication connections among the client terminals work together with call states of the phone terminals. In a communication network among the server and a plurality of client terminals; however, video sizes or data sizes in transmissions, use time zones or use environments, etc. increases a processing load or a traffic load sometimes, and occurs an error in session establishment among client terminals sometimes.
Up to now, a method, in which the server acquires quality information (usable codec/band information) of the client terminals to accomplish the session establishment from each client terminal, calculates optimum bands to notify them to each client terminal, calculates optimum bands to notify them to each client terminal, and then, establishes sessions in optimum bands among the client terminals, has been proposed (for example, Jpn. Pat. Appln. KOKAI Publication No. 2005-129981).
However, in the method, the server executing a process from acquiring the quality information of the client terminals up to the session establishment among the client terminals, the processing load on the server becomes heavy. This fact becomes clearer as the scale of the VCS becomes larger.